Plant protein product and process

ABSTRACT

ALFAFA AND CLOVER, CONTAINING NATURAL PROTEIN, IS TREATED WITH AN AQUEOUS BASIC SOLUTION, THE RESULTING EXTRACT IS DIGESTED AT A PH OF ABOUT 6 TO 14 WITH PANCREATIN AND THE UNDISSOLVED MATERIAL IS SEPARATED FROM THE AQUEOUS DIGESTED EXTRACT TO FORM AN EDIBLE PRODUCT.

UnitedStates Patent 3,780,183 PLANT PROTEIN PRODUCT AND PROCESS GeorgeWheeler Edwards and Arrie Wood Edwards, both of Rte. 4, Kay Drive,Jackson, Tenn. 38301 No Drawing. Filed Jan. 25, 1971, Ser. No. 109,714Int. Cl. A23k 1/00 US. Cl. 426-50 15 Claims ABSTRACT OF THE DISCLOSUREAlfalfa and clover, containing natural protein, is treated with anaqueous basic solution, the resulting extract is digested at a pH ofabout 6 to 14 with pancreatin and the undissolved material is separatedfrom the aqueous digested extract to form an edible product.

This invention relates to foods for humans and lower animals. Moreparticularly, this invention is concerned with a food product obtainedfrom plants which are not generally considered directly consumable byhumans, and to a process of producing such a product.

Alfalfa and clover contain crude protein and are used commonly as foodfor ruminants and other animals. While they contain protein in amountsuseful for human feed, such plants have been used only sparingly forhuman food. There are reasons for this. One is that the plants tastebad. Another is that many of them are indigestible. The production ofacceptable human food from such plants, however, continues to beinvestigated because of the present and future needs for new foodsupplies. It has been recognized that humans cannot forever rely on meatas their primary protein source. The production of protein by animalhusbandry is slow, expensive and inefficient, and in the case of largeanimals requires much land and feed. The continued increases in thehuman population make it abundantly clear that humans must seek proteinfoods from plants.

There is accordingly provided by the subject invention a novel humanfood product high in protein as well as carbohydrates, vitamins,minerals and essential amino acids, produced from plant raw materials,and a process of producing such a product. The product, in addition, canbe used as food for lower animals. By-products of the process are alsoobtained which constitute excellent animal food.

In producing the product of this invention alfalfa or clover is firstbrought into contact with an aqueous solution of a base which will notleave a residue which may adversely affect the suitability of theproduct or leave it unpalatable. The aqueous basic solution digests theplant material and this yields an aqueous extract. The aqueous extract,with or without a prior separation of undissolved material, is thentreated at least with pancreatin to convert starches into solublecarbohydrates, digest lipids and release protein hydrolysates. Theresulting aqueous solution, advisably after separation of lipids andlipoproteins, can be added to other foods without prior concentration,or it can be concentrated by removal of water before being so used.

In practicing the first main step of the process, alfalfa or clovercontaining a significant amount of naturally occuring protein can beused. The materials presently considered most suitable are cut alfalfaand dehydrated alfalfa with dehydrated alfalfa being the startingmaterial of choice.

While a considerable number of basic materials can be used for theextraction, it is advisable to employ an alkali metal hydroxide orcarbonate, or an alkaline earth hydroxide or carbonate, or anycombination of these bases in aqueous solution. Sodium hydroxide, sodiumcarbonate,

3',780"l83 Patented Dec. 18, 1973 potassium hydroxide, potassiumcarbonate, magnesium hydroxide, magnesium carbonate and calciumhydroxide and mixtures thereof are specific bases which can be used inaqueous solution. Sodium hydroxide, because of its low cost,effectiveness, suitabilit for use in food processing and readyavailability, is advisably employed.

The concentration of the aqueous basic solution used in digesting theplant material is not narrowly critical. However, it should advisablyhave at least a pH of 8 or higher. While solutions containing higherquantities of a base can be used, there is no advantage, and sometimesdisadvantages, in using an aqueous solution containing more than 10% byweight of a base. In the case of sodium hydroxide, a solution containinghigher than 7.5% by Weight of this base is generally unnecessary. It ispresently considered that an aqueous basic solution having a pH of about8 to 14 gives the best results. Particularly useful is a 0.33% by weightsolution of sodium hydroxide in water having a pH of 10.5.

The ratio of the amount of plant material by weight to the volume of theaqueous basic solution used for the extraction is not narrowly critical.However, from about 1 to 5 liters of aqueous basic solution can besuitably employed to extract one pound (454 g.) of plant material. It isconsidered advisable for optimum processing to use sufficient basicsolution so that the pH of the resulting extraction slurry does not dropsignificantly below pH 8 as a result of the formation of acidicsubstances by the extraction.

The extraction can be readily effected by forming a slurry of the plantmaterial in the aqueous basic solution. The extraction is advisablyeffected at an elevated temperature up to the boiling temperature of thesolution. The aqueous basic solution can be pre-heated before it iscombined with the plant material or a slurry of the plant material inthe aqueous basic solution can be first formed and the slurry thenheated. Stirring of the slurry during the extraction is advisable. Theextraction is considered completed after about 30 minutes to 2 hours,depending on the temperature of the extraction. When the slurry isboiled, an extraction time of 30 minutes to 1 hour is generallysuitable.

After the digestion or extraction with the basic solution is terminated,the slurry is brought to a temperature of about 38 C. to C., withoutseparating the liquid phase from the dispersed solids but withadjustment of the slurry to about pH 6 to 14 if necessary, andpancreatin is added thereto. When a strong basic solution is used forthe digestion, the resulting extract will be more basic than suitablefor pancreatin stability and effectiveness. An acid may accordingly beadded to lower the extract pH to a level which favors pancreaticactivity. Generally, enough acid may be added to bring the pH of theextract to about 6 to 14. Any suitable acid may be used for this purposebut phosphoric acid is advisably employed since it exerts a bufferingaction. Hydrochloric acid and sulfuric acid are some other mineral acidswhich can be used. Organic acids that may be used are citric acid,acetic acid and succinic acid.

The most suitable temperature range for effecting the pancreatintreatment appears to be about 40 C. to 50 C. The amount of pancreatinadded is not narrowly critical but a sufiicient amount should be addedto convert the proteoses and starches to soluble carbohydrates, proteinsand amino acids. In general, about 0.2 g. to 5 g. of pancreatin can beadded per pound of plant material used as starting material. The mostsuitable range, however, appears presently to be about 0.5 g. to 1 g. ofpancreatin per pound of plant starting material, particularly whenalfalfa is the starting material. The inclusion of about 0.5 g. to 1 g.of corn and potato starch amylase per pound of starting material, withthe pancreatin, is beneficial and aids in reducing bitterness in thefinal product.

The slurry incubation with pancreatin is continued for sufficient timeto efiect the desired conversion. Usually from about 12 to 48 hours issufiicient although a longer period does no appreciable harm. Afterdigestion with pancreatin for 24 hours, the slurry can be expected tohave an odor somewhat like grapefruit juice. As a result of thepancreatin treatment, the slurry pH may drop to about to 6.

Following the pancreatin incubation, the slurry is separated into asolid phase and a liquid phase by any suitable means, such asfiltration, centrifugation or decantation. When the product is filtered,the filtered extract may develop a greenish black substance comprisingdecomposed chlorophyll and lipids which settle out. This substance canbe removed by centrifugation or gravity settling. The liquid extractconstitutes a human and animal food product rich in digestible protein,carbohydrates, essential amino acids, vitamins and minerals. The liquidextract, containing about 4 to 5% solids, can be added to other foods.It can be concentrated, however, by a number of means to raise thesolids concentration up to about 50 to 100%. One method of concentrationis to heat the liquid extract to boiling to evaporate water. However,the pH of the liquid extract advisably is adjusted to a pH of about 4 to5 by the addition of a mineral acid before the evaporation. Phosphoricacid and hydrochloric acid or some other acid can be used for this pHadjustment. Thin channel ultrafiltration can also be used to concentratethe liquid extract. At a concentration of about 40% solids the productcan still be poured and pumped easily. More concentrated solutionsbecome viscous and are more difiicult to handle. However, liquidextracts of this invention can be spray dried onto a solid particulatecarrier using conventional techniques to produce a free flowing solidedible composition. When dried at 100 C. it forms a hydrogel.

The invention also provides important variations and supplementaryprocedures which can be employed in conjunction with the key steps ofthe process already described and which lead to even more usefulproducts.

One important supplementary procedure is to inoculate the slurry,obtained from the aqueous basic solution eX- traction, with a suitableyeast simultaneously or contemporaneously with the addition of thepancreatin. The c0nditions employed for the pancreatin treatment can beselected to be highly conducive to yeast growth in the slurry and thegrowth of yeast induces a highly beneficial conversion of products inthe slurry into materials advantageously present in a human food. Thegrowth of yeast, in itself, provides a protein supplementation which isdesirable in the product. Any suitable yeast can be employed but forsimplicity, common bakers yeast (Saccharomyces cerevisiac) is advisablyused. Torula utilz's is another suitable yeast. About 1 g. to 2 g. ofyeast per pound of plant starting material is adequate although more orless yeast than this can be used. Adding yeast with the pancreatin tendsto increase the protein content and to decrease the ash content, thelatter of which is often desirable, of the product. When yeast is used,the product can be worked up in the same way as described for the use ofpancreatin without yeast, using an incubation period of about 12 to 48hours.

A second significant supplementary procedure which can be usedconstitutes a treatment of the slurry obtained from the pancreatindigestion, and advisably before separation of undissolved solidstherefrom, whether or not yeast has been used in conjunction with thepancreatin, with another enzyme or mixture of enzymes. Potato-cornstarch amylase, pepsin, trypsin, papain, hog pancreas diastase, maltdiastase, steapsin, cellulase and pectinase are specific enzymes whichcan be used. However, any enzyme which acts on protein, lipid orcarbohydrate can be used. Potato-corn starch amylase is presentlyconsidered the best choice. The use of one or both of these enzymes inthe process leads to an even more suitable product. The amount of enzymeadded is not narrowly critical. Usually about 0.1 g. to l g. of enzymeper pound of plant starting material is suitable although more or lessthan this can be used. During such treatment, which can continue forabout 12 to 48 hours, the slurry is advisably maintained at atemperature of about 38 C. to C. with 45 C. considered optimum. Inaddition, the extract is advisably adjusted, if necessary, to pH 8 to 10to obtain maximum enzyme efiectiveness. Treatment with the enzyme asdescribed can be expected to bring the slurry pH down from about 7 toabout 5 especially if no buffer such as phosphoric acid is present. Whensuch a supplementary procedure is used, the resulting slurry can beworked up as already described. It thus can be filtered to separateundissolved solids and then the liquid extract can be concentrated ifdesired.

For human use, the liquid extract is desirably further treated to removechlorophyll and lipoproteins. These materials can be removed by aging toallow lipoprotein to settle followed by filtering the liquid extractthrough cotton. The lipids can be removed from the cotton by washing thecotton with acetone or some other organic solvent in which lipids orfats are soluble.

The resulting product generally has about 4 to 5% solids and is a lightbrown liquid and is stable without refrigeration. For human use, it isadvisable to adjust the pH of the extract with an acid to about 4 to 5depending on the food to which it is to be added. A mineral acid ororganic acid is advisably used for this purpose, and advisably one whichis acceptable in foods. Acetic acid, hydrochloric acid, phosphoric acid,sulfuric acid, succinic acid and citric acid are some acids which can beused for this purpose. The product can be concentrated by boiling offwater until any suitable concentration of solids is obtained. When thesolids concentration reaches about 4050%, the product becomes quiteviscous and as the solids concentration increases it becomes thicker andflows slower. The solid content can be increased up to a hydrogel verysimilar in texture to cooked raisins or dried fruit. It does not form acrystal or free flowing solid but it can be absorbed onto a carrier forthe production of a granular product.

The product of this invention constitutes a food which can be absorbedinto the blood stream with little digestion. It is low in lipids.

The product can be added to fruit and vegetable juices, starch productssuch as bread, rolls and cakes, blancmange, chocolate foods of alltypes, ice cream, ice milk, ground and comminuted meats such ashamburger meat and sausage meat, other plant protein foods, soups,cookies and candy using products which have an appropriate solidscontent for use in the foodstufi.

The product can function as a wetting agent for less soluble proteinfoods and as a water retaining material in foods. It also constitutes acomplete growth medium for Lactobacillus arabinosus, L. fermenti, L.Casei and other bacteria. It can be used as a caragheen extender infoods such as ice milk, ice cream and candy. It is also a good acidbuffer.

The product, in addition to its protein and carbohydrate content,contains A and B vitamins.

The residue obtained from the process after filtration of the enzymetreated slurry can be dried and used in all types of animal feed. It canalso be used in brewing tea in which it can be used in admixture withtea leaves. The residue can also be retreated as described with anaqueous basic solution to form an extract and the extract can bedigested with pancreatin to form a liquid extract which can be used asan animal feed. The lipoprotein fraction separated in the process canalso be used in animal feed.

EXAMPLE 1 113 grams (0.25 lb.) of alfalfa meal is added to 850 ml. of anaqueous 0.33% sodium hydroxide solution. The

mixture is boiled for one hour. The solution is cooled to 45-50" C. andthen 0.125 g. of pancreatin and 0.25 g. of bakers yeast are added. Themixture is incubated for 48 hours. The greenish black lipoprotein wasseparated by 'decantation and the liquid extract containing 5% solidswas evaporated to a product containing 50% solids. The extract contained28% of the 113 g. of starting alfalfa meal. The extract solids analyzed:crude protein, 19.20%; fat, 0.231%; crude fiber, 0.037%; nitrogen freeextract carbohydrates, 80% and ash, 0.37%.

EXAMPLE 2 100 grams of alfalfa meal is added to 400 ml. of a 7.5%aqueous solution of sodium hydroxide and the mixture is boiled for onehour. The mixture is diluted to 750 ml. with water and 85% phosphoricacid is added to pH 8-10. The procedure of Example 1 is then followed.The resulting aqueous extract constitutes 60%, and the residue 40%, ofthe starting alfalfa meal.

EXAMPLE 3 One pound of alfalfa meal containing 17.522% protein and 715%water is mixed with 3 liters of 0.3% sodium hydroxide and heated at alow boil for one to two hours. The mixture is cooled to 4550 C. andincubated for 12-48 hours with 0.51.0 g. of pancreatin. The enzymaticreaction is very active after 24 hours and carbon dioxide is liberated.The pH drops to 5-6. The extract is separated from the residue andallowed to age for 24-48 hours in a suitable container-polyethyleneplastic bottle is suitable. A greenish black lipoprotein layer settlesto the bottom. The brown supernatant is decanted from the top through aloose plug of cotton to remove any remaining suspended green or blackparticles. The pH is lowered to 4 with phosphoric acid. The extract (5%solids) is heated to remove Water and increase the solid content. Thesolid content can be increased up to a level which yields a hydrogelvery similar to cooked raisins or dried fruit.

EXAMPLE 4 One pound of alfalfa meal (17.5 to 2 2% by weight protein and7 to by weight water) is added to 3 liters of a 0.33% aqueous sodiumhydroxide solution. The resulting slurry is mixed and boiled for :1 hourwith stirring during which the slurry pH drops from 10.5 or above toabout 8. The slurry is cooled to 45 C. and inoculated with 1 g. ofpancreatin and 2 g. of bakers yeast and incubated at 45 C. for 24 hours.The slurry pH is about 5-7 after the incubation. The slurry is thenfiltered through a strong cotton cloth. The aqueous filtrate has a pH ofabout 6 and contains about 5% solids. The solid residue on the filter isremoved, dried and saved for use as animal feed. The extract, afteraging for 24 hours, is dripped through a cotton plug to removechlorophyll and lipids. The filtrate (5% solids) is acidified to pH 4-5with phosphoric acid and boiled until the solution contains about 10%solids by weight. The product can be further concentrated to 50100%solids.

EXAMPLE 5 One pound of the residue from Example 4 is treated with 1.5liters of 10% sodium hydroxide for 2 hours at the boiling point. Thesolution is diluted to 9 liters and pH adjusted to 8-9 with hydrochloricacid. Incubation is carried out with 0.5 g. of pancreatin and 0.5 g. ofpotato-corn starch amylase for 48 hours. An aqueous suspension of 5%solids is formed. Any large particles which are present after digestionand do not suspend can be treated by repeating the digestion process orby treating with a fast speed blender. The material is dark green incolor and is used as an animal feed. It can be dried to a green solid ifdesired. It can be pumped and mixed with other feed and is a feed forswine and other animals.

6 EXAMPLE 6 Alfalfa Sloppy Joes Brown the ground beef in vegetable oil;add onion and green pepper and cook about five more minutes. Stir inflour, soup, catsup, alfalfa extract and Worchestersire sauce and cookuntil thickened. Season with salt and pepper and serve on hamburgerbuns.

EXAMPLE 7 Alfalfa Spiced Tea A cup alfalfa residue from Example 4 A; cuploose tea /2 teaspoon ground cloves /2 teaspoon ground cinnamon /2 cupsugar cup orange juice 6 cups boiling water To 6 cups boiling water add/2 cup sugar and stir until sugar dissolves. Tie alfalfa residue, teaand spices in a bag, loosely. Drop bag in sugar water solution and allowto simmer at least 10 minutes. Add A cup orange juice. Serve hot. May bereheated as desired.

EXAMPLE 8 Chocolate Blancmange 2 envelopes plain gelatin 3 /2 cups milk2 one-ounce squares unsweetened chocolate 1 cup sugar 2 tablespoonsalfalfa extract (10% solids, Example 4) 1 teaspoon vanilla Soften thegelatin in /2 cup milk. Heat remaining milk. Add chocolate, sugar,alfalfa extract and vanilla and stir until the sugar is dissolved. Pourover gelatin and stir until dissolved. C-hill until set. The taste isnot changed by the alfalfa, but the texture is greatly improved,creamier.

EXAMPLE 9 Butterscotch Drops /2 cup sugar cup light corn syrup A cupalfalfa extract (10% solids, Example 4) 1 tablespoon butter /2 teaspoonvanilla Dash butter rum flavoring Combine sugar, corn syrup and extract;bring to boil; cook over low heat; stir until sugar is dissolved. Cookwithout stirring to hard-ball stage. Add butter; cook to soft-crackstage. Remove from heat and add butter rum flavoring and vanilla. Dropfrom teaspoon to greased baking sheet. No change in taste due to thealfalfa extract.

EXAMPLE 10 3 or 4 tablespoons of alfalfa extract (5-10% solids) may besubstituted for that much water in making a can of soup. No change intaste.

EXAMPLE 11 A cup alfalfa extract (540% solids) may be blended into oneroll of refrigerated cookie dough or added to any cookie recipe. Cookieswith the extract stay fresh longer.

EXAMPLE 12 grams of alfalfa was added to 150 ml. of 0.166% sodiumhydroxide and the mixture boiled for 10 minutes. After boiling, the pHof the mixture was 8 to 9. To the mixture at 40 C. was then added 0.01g. of pancreatin and 0.01 g. of pepsin. The mixture was then incubatedfor 3 hours. The pH of the mixture was 8, and the amount of the extractwas 2.7 g., after 3 hours. At the end of 21 hours of incubation, the pHwas 7 and the amount of the extract was approximately 3.6 g. The residuewas about 6.5 g. The extract was then further processed as in Example 1.

What is claimed is:

1. The process which comprises treating a plant substance of the groupconsisting of alfalfa and clover, containing natural protein, with anaqueous basic solution, digesting the resulting slurry at a pH of about6 to 14 with pancreatin, and separating the dissolved and undissolvedmaterials from the aqueous digested slurry, both said dissolved andundissolved materials being useful as food substances.

2. The process of claim 1 in which the aqueous basic solution containsan alkali metal hydroxide or carbonate or an alkaline earth metalhydroxide or carbonate.

3. The process of claim 1 in which the plant substance is dehydratedalfalfa.

4. The process of claim 1 in which the pancreatin digestion is expectedat about 38 C. to 75 C.

5. The process of claim 1 in which a yeast, suitable for food, isincluded during the pancreatin digestion.

6. The process of claim 1 in which an enzyme, in addition to pancreatin,which acts on protein, lipid or carbohydrate is included with thepancreatin.

7. The process of claim 6 in which the enzyme is potato-com starchamalyse, pepsin, trypsin, papain, hog pancreas diastase, malt diastase,steapin, cellulase or pectinase.

8. The process of claim 2 in which the aqueous basic solution used has apH of at least 8.

9. The process of claim 1 in which the concemration of the aqueous basicsolution gives a pH not less than 8 and the solution contains up to 10%by weight of basic material.

10. The process which comprises treating alfalfa with an aqueous basicsolution having a pH not less than 8 and containing up to 10% by weightof basic material at an elevated temperature up to the boilingtemperature of the solution, adjusting the pH of the slurry to about 8to 10 when necessary, adding pancreatin to the slurry at about 38 C. toC., separating solids from the liquids of the slurry after thepancreatin digestion is terminated, both said solids and liquids beinguseful as food substances.

11. The process of claim 10 in which the basic material is sodiumhydroxide.

12. The process of claim 10 in which the pancreatin digestion continuesfor about 12 to 48 hours.

13. The process of claim 10 in which the slurry from the pancreatindigestion is evaporated to increase the solids content to at least 30%.

14. The process of claim 10 in which yeast, potatocorn starch amylase,pepsin, trypsin, papain, hog pancreas diastase, malt diastase, steapin,cellulase or pectinase is included with the pancreatin digestion.

15. A plant extract aqueous solution produced according to the processof claim 1.

References Cited UNITED STATES PATENTS 3,220,851 11/1965 Rambaud 99173,018,280 1/1962 Salzberg 9917 2,051,017 8/1936 Schwarz 9917 3,258,4076/1966 Blanchon 9917 3,516,349 6/1970 Bertullo et a1. 9917 2,930,7003/1960 Bradof 99,-99 3,637,396 6/1971 Hollo et a1. 999

A. LOUIS MONACELL, Primary Examiner R. M. ELLIOTT, Assistant ExaminerUS. Cl. X.R. 426-5 3, 212

. UNITED STATES PA'fEN'IfZ O FEICE CERTIFICATE OF CORRECTION Patent: No.3,780,183 Dated December 18, 1973 Inventor(s) George Wheeler Edwards etal.

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

Column 7, Line 30, change.?expected" to effected--.

Signed and sealed this 16th day of July 1974- (SEAL) Attest:

MCCOY M. GIBSON, JR. c. MARSHALL DANN Atteting Officer Commissioner ofPatents

